Sparks are flying following the disclosure that genetically modified maize has been found growing in Mexico, the global centre of maize diversity and the place of origin of strains grown around the world.

Although transgenic maize is widely sold for consumption in Mexico, its commercial cultivation there is prohibited following a 1998 government moratorium.

But researchers from the University of California at Berkeley — who are preparing work on the topic for publication — found scattered plots of transgenic maize growing in Mexico. Environmental groups claim that the arrival of transgenic strains could disrupt the genome of naturally bred maize.